Copper Alloys Naval Brass C46400 – Austral Wright Metals

Product Data Sheet – Copper Alloys

Naval Brass, Uninhibited  UNS-C46400

Mechanical Properties

Blanking, Drawing, Forming and Bending, Heading and Upsetting, Hot Forging and Pressing, Hot Heading and Upsetting, Shearing

Fabrication Properties

Typical Uses

Phase Diagram & Mechanical Properties

Corrosion Resistance

The addition of tin gives this alloy an inherent resistance to dezincification, further inhibiting the impingement by seawater at higher than normal temperatures. C46400 naval brass is also noted for its resistance to wear, fatigue, galling, and stress corrosion cracking.

C46400 has good corrosion resistance to weathering and good resistance to many waters. It was developed to resist the dezincification in sea water which may be encountered with plain 60:40 brass, C28000.

Low-copper alloys, such as naval brass appear to form thin, adherent surface films of corrosion products which are moderately protective.

C46400 should not be used in contact with ammonia, ammonia compounds or amines, as it may suffer stress corrosion cracking. It may also suffer stress corrosion cracking in atmospheric exposures.

Please consult Austral Wright Metals for advice on your specific application.

Marine Atmospheric Exposure

Copper alloys are often specified for marine atmospheric exposures because of the attractive and protective patina they form during the exposure by mild surface corrosion. The corrosion rate slows during the exposure.

Naval brass generally darkens to a deep chocolate brown colour. It is not expected to form the green patina often seen on alloys richer in copper, especially on material mounted vertically.

Differences between the corrosion rates of various alloys do exist, but they are usually less than the differences caused by the environment. Copper alloys can be classed into a group that corrodes at a moderate rate (high copper alloys, silicon bronze, tin bronze) and a group that corrodes at a slower rate (brass, aluminium bronze, nickel silver, copper nickel).

The average metal thickness loss, d, of the former group approximates to d = 0.1 t2/3, and of the latter group to d = 0.1 t1/3, where t is the exposure time.

The surface can be artificially bronzed to produce by the patina, please contact Austral Wright Metals for details. Both artificial and naturally patinated surfaces will continue to darken unless washed hot soapy water, rinsed, dried and treated with lemon oil, boiled linseed oil or castor oil. The surface will take on a mild lustre.

This sequence of washing and oiling should be repeated at about yearly intervals to maintain the metal in good condition.

Moderate corrosion rate group (high copper alloys, silicon bronze, tin bronze)		Low corrosion rate group (brass, aluminium brass, nickel silver, copper nickel)

The surface can be artificially bronzed to produce by the patina, please contact Austral Wright Metals for details. Both artificial and naturally patinated surfaces will continue to darken unless washed hot soapy water, rinsed, dried and treated with lemon oil, boiled linseed oil or castor oil. The surface will take on a mild lustre.

This sequence of washing and oiling should be repeated at about yearly intervals to maintain the metal in good condition.

Physical Properties

Tempers Most Commonly Used